Transcript Ch9LabNotes

Router Fundamentals
(Ref. CCNA5 Introduction to Networks 2.1, 6.3)
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A Router is a Computer
Router CPU and OS
Operating System
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Cisco IOS – Collection of network operating systems
used on Cisco devices
All networking devices come with a default IOS
Switch or router IOS provides options to:
 Configure interfaces
 Enable routing and switching functions
Possible to upgrade the IOS version or feature set
Location of the Cisco IOS
Cisco IOS stored in Flash
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Non-volatile storage, not lost when power is lost
Can be changed or overwritten as needed
Can be used to store multiple versions of IOS
IOS copied from flash to volatile RAM
Quantity of flash and RAM memory determines IOS that can be used
Router Memory
Memory
Volatile /
Non-Volatile
Stores
Volatile
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Running IOS
Running configuration file
IP routing and ARP tables
Packet buffer
ROM
Non-Volatile
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Bootup instructions
Basic diagnostic software
Limited IOS
NVRAM
Non-Volatile
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Startup configuration file
Flash
Non-Volatile
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IOS
Other system files
RAM
Connecting to a Router
WAN
Interface
AUX
Port
Console
RJ45
Console
USB Type B
LAN
Interfaces
Accessing a Cisco IOS Device
Most common methods to access the CLI:
 Console
 Telnet or SSH
 AUX port
Console Access Method
Console Port
Device
is accessible even if no networking services have been
configured (out-of-band)
Need a special console cable
Allows configuration commands to be entered
Should be configured with passwords to prevent unauthorized access
Device should be located in a secure room so console port cannot be
easily accessed
Telnet, SSH, and AUX Access
Telnet
 Method for remotely accessing the CLI over a network
 Require active networking services and one active
interface that is configured
Secure Shell (SSH)
 Remote login similar to Telnet, but utilizes more security
 Stronger password authentication
 Uses encryption when transporting data
Aux Port
 Out-of-band connection
 Uses telephone line
 Can be used like console port
Terminal Emulation Programs
Software available for
connecting to a networking
device:
PuTTY
Tera Term
SecureCRT
HyperTerminal
OS X Terminal
Router Boot-up
Screenshot of Loading Bootstrap
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IOS Software Configuration Modes
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Primary Modes
Global Configuration Mode and
specific configuration modes